As a communication terminal provided with a small liquid crystal display device, cellular phones and car navigation terminals have been known. For example, in the car navigation terminal, the user designates a goal point by entering information on the goal point on a menu screen, in order to search for a root to the goal point. When the user chooses a goal-setting menu, the menu screen displays several entry items for designating the goal point, e.g. telephone number, address, registered points, and so forth. When the user chooses a search based on the address, candidates for a local area, a city or town, and address numbers are displayed hierarchically, so that the user may choose these items sequentially, as disclosed for example in Japanese Laid-open Patent Application No. 2000-314636. The candidate items of the same class or hierarchical grade are usually displayed in the same window, and a subordinate window is displayed in front of an upper class or main window.
Once the subordinate window is displayed, the upper class window is hidden behind the subordinate window. Therefore, it sometimes happens that the user cannot instantly recognize the fact that the choice made in the upper class window is wrong. To solve this problem, Japanese Laid-open Patent Application No. 2003-263256 suggests a multi-window display system, which displays windows while shifting their positions from each other, so that the items offered in a main window are partly displayed even after a subordinate window is displayed in response to a choice from the items in the upper class window. Also a window display system displaying an upper class window in an enlarged size to display a subordinate window inside the upper class window has been known from Japanese Laid-open Patent Application No. 2001-306209.
However, the window display systems disclosed in the second and third mentioned prior arts need a large screen for displaying a plurality of windows. In order to apply these systems to a display device with a small screen, it is necessary to reduce the font size and the like to reduce the respective sizes of the windows, which worsens the user-friendliness of the display screen.